1. Field of The Invention
The present invention relates to a fixing device in a venetian blind, and particularly to an improvement of a fixing device for a bracing cord and a positioning band in a venetian blind.
2. Description of Related Art
Usually, a venetian blind is a very popular window shade and is one of basic arrangements adopted when building a house. In order to block the light as desired, the venetian blind can be operated to locate the slats thereof at a specific height and to move the slats angularly as desired respectively.
As shown in FIG. 5, it is know that a venetian blind has a rod B at the top thereof and fixing devices are mounted on the rod B at a certain interval to fix the bracing cord or the positioning band. In addition, the cord or the band may move downward and be associated with the slats such that a controller at a lateral side of the venetian blind can be operated to turn the slats and to adjust the height of the slats.
The fixing device mentioned above is used to fix the bracing cord or the positioning band. How to fix the bracing cord or the positioning band and how to fix the fixing device on the rod B are subjects have to be considered virtually.
Originally, a conventional fixing device in a venetian blind is divided into two types: one is designed for fixing a bracing cord and the other one is designed for fixing a positioning band. In order to reduce the production cost and the inventory cost, a dual fixing device was developed, which can not only fix the bracing cord but also the positioning band, instead of using two different fixing devices.
For instance, U.S. Pat. No. 5,573,052, which is entitled "POSITIONING DRUM DEVICE FOR A VENETIAN BLIND", is a dual fixing device for fixing the bracing cord and the positioning band respectively. The device provides two opposite fixing faces such that one of which admits and fixes the bracing cord and the other one of which admits and fixes the positioning band. A closed end portion at the fixing face for the positioning band has two extending elongated rods to perform a fixing job. Two parallel head rails and a passage are provided on the fixing face to be passed through by the cord and performing a fixing job.
Although a dual fixing device can achieve the basic function required for fixing the bracing cord and the positioning band, the elongated rods are parallel to each other and attached to an inner wall of the closed end portions. It results in a force exerting in a direction perpendicular to the inner wall such that a great stress may cause to create a problem of insufficient strength. It is a tedious work to repair or replace the venetian blind after it is out of order such that a life span for a venetian blind is a factor that has to be considered while the venetian blind is made. Furthermore, there are several fixing devices that have to be mounted on a shaft at least so that the orientation of each fixing device has to be located correctly when the assembling job is executed and it often leads to a substantially lower working efficiency. In addition, both lateral sides of each fixing device are flatly cut faces and provided with a central hole respectively available for the shaft passing through such that the shaft subjects to a heavier load. Thus, an engaging seat A fitting with an upper rail becomes useless so as to lessen the durability of the fixing device.